call time pass by reference

[Ben Sth. <ben...@or...>]

hi list

just wondering wether this is a serious warning/error or not worth
mentioning:

Warning: Call-time pass-by-reference has been deprecated - argument passed
by value; If you would like to pass it by reference, modify the declaration
of method_exists(). If you would like to enable call-time pass-by-reference,
you can set allow_call_time_pass_reference to true in your INI file.
However, future versions may not support this any longer. in
xxx/xpath/xpath.class.php on line 3156

I get this error when including the xpath class. I once read about
performance reasons why to use this pass-by-reference thing. but in fact I
do not know a lot about it...

cheers
ben